The survey also shows major differences of opinion among voters of various ethnic groups and political parties, and whether they were born in the United States.

Overall, a majority of voters continue to believe that illegal immigrants have a negative effect on California, though less so than in past decades.

Field Poll Director Mark DiCamillo said he was struck by the strength of voters’ opinions on both sides.

“It certainly pits two very strongly held opposite factions against one another,” DiCamillo said.

Passage of the Arizona law this spring reignited the already intense debate over illegal immigration. The law gives police the right to question people suspected of being in the country illegally and ask them for verification of their legal status.

Andrea Guerrero of the San Diego chapter of the American Civil Liberties Union said Thursday that she had seen higher poll numbers in favor of the Arizona law in the past and that as more people learn that it is “not a fix to the immigration system,” support for it will wane.

“This is an aggressive attack on civil liberties and civil rights,” she said.

Andy Ramirez, who has spent time monitoring the U.S.-Mexico border in East County for illegal crossings, said the federal government is “refusing to allow their agents to enforce immigration” laws, so states and communities are trying to fill the gap.

Ramirez, the founder of a Southern California nonprofit that supports law enforcement, said he believes officers will enforce the law while respecting people’s rights.

Critics say the law will encourage racial profiling and harassment; defenders contend it is necessary because the federal government has failed to curb the flow of drugs and illegal immigrants across the border. The law has triggered protests across the country and this month the federal government took the unusual step of filing a lawsuit seeking to throw out the law, saying it violates the Constitution.

In contrast to California, a recent national poll that showed 60 percent of Americans support the law, DiCamillo said.

He attributed the difference in part to stronger opposition to the law among state Latino voters than was seen nationally.

According to the new poll, 71 percent of California Latino voters oppose the Arizona law, while 24 percent support it.

Most other ethnic groups surveyed came out on the opposite side of the debate, with white non-Hispanics backing the law 58 percent to 37 percent and African-Americans supporting it 53 percent to 39 percent. Asian-Americans were the most closely divided, with 50 percent saying they supported the law and 43 percent opposing it.

“(On) most issues the ethnic groups, generally speaking, tend to be on the same sides,” DiCamillo said. Here, he added, “you have very different views on this issue across those populations.” The data also showed a wide disparity depending on the respondents’ place of birth.

U.S.-born voters favored the Arizona law 54 percent to 41 percent; just 28 percent of those born outside the U.S. said they backed it.

One of the strongest single blocs of support came from registered Republican voters, 77 percent of whom said they favored the law. Meanwhile, 62 percent of Democrats said they disagreed with the law, and nonpartisans were about evenly divided.

Only about one in four voters who said they preferred the gubernatorial bid by Attorney General Jerry Brown, a Democrat, or a re-election bid by U.S. Sen. Barbara Boxer, D-Calif., approved of the Arizona law. But four of five supporters of former eBay executive Meg Whitman, the Republican running for governor, or former Hewlett-Packard executive Carly Fiorina, the Republican candidate for U.S. Senate, said they backed the law.

Whitman has come out against the Arizona law; Fiorina favors it. Voters who are undecided in the governor’s race support the new law and undecided voters in the Senate race are divided with 49 percent in support.

Opinions were strong on both sides. Of the 49 percent of voters who said they approve of the Arizona law, 37 percent said they approved strongly. Likewise, of the 45 percent who disapproved of the law, 34 percent said they disapproved strongly.

The poll shows that most California voters continue to believe illegal immigrants have a negative effect overall on the state, but that view has steadily diminished for three decades. Fifty-six percent of those surveyed said illegal immigrants have an unfavorable effect on the state, compared with 75 percent in 1982 and 67 percent in 1994.

The poll was based on telephone interviews in six languages and dialects of 1,390 registered state voters between June 22 and July 5. It has a margin of error of 2.8 percentage points.